Server-sent events in Play2 / Iteratee for Hystrix console

sse.scala

import play.api.libs.concurrent._
import play.api.libs.concurrent.Execution.Implicits._
import play.api.libs.iteratee._
import scala.concurrent.duration._

  def circuitBreakers = Action {
    Ok.stream(Enumerator.generateM {
      val promise = Promise[String]()
      Akka.system.scheduler.scheduleOnce(1 second) {
        promise.completeWith(circuitBreakers)
      }
      promise.future.map { msg => Some(msg) }
    }).as("text/event-stream")
  }

  // `data: ` is important
  def circuitBreakers = {
    import play.api.libs.json.Json
    import models.InsightsModels.HystrixCommandWrites
    val now = System.currentTimeMillis
    val window = 10
    try {
      Future.sequence(stats2breaker.map {
        case (service, breakerName) =>
          serviceStatus(window, service).map { stats =>
            val requests = stats.wsCallSuccess + stats.wsCallFail
            val percents = if (requests > 0) (100 * (stats.wsCallFail / requests.toDouble)).toInt else 0
            "data: " + Json.stringify(Json.toJson(HystrixCommand(breakerName, now,
              CircuitBreakerStateHolder.currentlyOpen().map(_._1).contains(breakerName),
              percents, stats.wsCallFail, requests, stats.cacheHit, stats.wsCallSuccess, stats.wsCallTime, window)))
          }
      }).map {
        _.mkString("", "\n\n", "\n\n")
      }
    } catch {
      case x: Throwable => Future failed x
    }
  }